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Lean Management Principles
By Prof. Rene T. Domingo
rtd@aim.edu
www.rtdonline.com
The Toyota Motor Corporation (TMC) of Japan pioneered the development and
implementation of the Lean Manufacturing System. Its purpose was to come
out with a highly effective and efficient manufacturing process of producing
cars and vehicles with high quality, low cost, and fast delivery through the
elimination of all forms of wastes. Lean ensures that there are positive
synergies among the quality improvement, cost reduction, and time reduction
programs of the company, and that no trade-offs and sacrifices are encountered.
Based on non-traditional concepts, this system enabled TMC to complete
globally in the highly competitive car market while maximizing the use of
scarce and expensive resources Japan is known for, like raw materials, labor,
fuel, and land. The Lean System and Lean Thinking were extended throughout
Toyota’s supply chain to achieve the highest operational results. Toyota
involved all its affiliates, major suppliers, contractors, distributors, and dealers
in TPS training and implementation. TMC also implements the Lean System in
its overseas plants and supply chain. The Lean System is also known as
follows, each label highlighting a particular principle of Lean Thinking:
“Just-in-time Production System”
“Kanban System”
“One-piece Flow System”
“Pull Manufacturing System”
Officially, TMC calls it the Toyota Production System (TPS). As TPS is
adapted in other manufacturing industries and lately in service industries, this
manufacturing philosophy is now commonly and more appropriately called
Lean System.
Rene T. Domingo
rtd@aim.edu
www.rtdonline.com
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What are the Basic Lean Principles of TPS?
The original and primary principle of the TPS is:
"Produce only what is needed, when it is needed, with the quantity needed."
Excess inventory due to overproduction was considered the biggest waste in a
manufacturing process that should be reduced continuously by imposing strict
discipline and rules in production flow and scheduling. Anything in excess of
what was needed to satisfy the customer was considered wasteful – be it raw
material, work-in-process, and finished goods. Later on, this principle would
be extended to unnecessary processing, man-hours, manpower, supplies,
storage, utilities, and equipment due to the production of excess inventories.
TPS was patterned after the US supermarket system wherein goods are
continuously replenished or restocked on the shelves with exactly the same
amount taken by customers. The shelves are always full, but not overstocked.
Supermarkets, having limited space, lots of product variety with fast turnover,
and products with short shelf lives, have to apply these strict “lean” principles
of “just-in-time” in order to survive and avoid huge losses due to overstocking
(spoiled goods) and under stocking (lost sales).
TPS adopts this “just-in-time” principle wherein a work station (factory,
process, or equipment) produces only what is needed by the next process which
could either be the external customer or buyer itself or another work station
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known as an “internal customer.” The quantity produced and delivered ideally
is the exact amount, no more no less, not early nor late at the place needed by
the next station. This principle is in contrast to the conventional manufacturing
concept of “Just-in-case” which allows early delivery, production and delivery
in excess of demand, and the carrying of safety stocks at all stations and
storage areas to cope with contingencies and variability.
The three basic production rules of TPS are
1) Never send defects to the next process.
2) The next process gets only what it needs from the prior process.
3) Produce only the quantity taken by the next process.
The first rule dictates that each station delivers only quality goods to the next
station, since the latter does not have spares nor the time to replace or rework
defects. The second rule means that the producer cannot push its output to the
next station; it should wait for the next station or “customer” to pull its required
quantity. Thus TPS is sometimes called the “Pull” system in contrast with
conventional system or “Push” system. The “Pull” system is similar to a train
in which the front engine, representing the customer, pulls everything behind it
and sets the pace and speed. The “Push” system is like a tractor that pushes
everything in front of it. “Pull” is customer driven, based on demand, while
“Push” is supplier driven, based on capacity. In a way, TPS is like a “make to
order” system while the traditional system is “make to stock”. The third rule
means that the producer can only replace what was taken by and delivered to
the next process. It cannot produce more than this amount, in contrast to
conventional systems in which production volume is based on capacity
utilization, economic order quantity, and batch size rules unrelated to actual
demand. By applying the three rules mentioned, the entire manufacturing
chain or supply chain in the full application of TPS, is expected to be inventory
free or “lean”, with inventory being considered “fat” that weighs down and
slows down the process.
Rene T. Domingo
rtd@aim.edu
www.rtdonline.com
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rtd@aim.edu
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Why is Excess Inventory considered Waste?
Inventory in whatever form for whatever reason is always associated with three
costs: carrying costs, management costs, obsolescence costs. Dramatic
reduction of inventory would therefore result in significant cost reduction and
savings for the company. Carrying costs include cost of money or working
capital to build up the stocks, insurance costs, and storage costs. Management
costs include supervision costs to manage inventory and its holding facilities,
information costs to track and record stock movements, quality costs to inspect
and audit the condition of the stocks, security costs to safeguard the inventory
from pilferage, fires, damage, and other contingencies. Obsolescence cost,
which can perhaps be the biggest of the three in these modern times, is
essentially the depreciation, diminution, total loss of the value of the inventory
because of lack of demand due to tough competition, unforeseen change in
consumer preference, rapid change in technology, or shortening of product life.
The most vulnerable to obsolescence risk is finished goods, followed by workin-process, and lastly by raw materials. Should demand change, the last two
types of inventory, to some extent, may still be saved from obsolescence and be
converted to the required finished goods. In this regard, TPS gives priority to
the just-in-time production of finished goods. Any excess would be the most
wasteful inventory because of their high value and inflexibility. Losses would
usually come from heavy discounting or eventually scrapping or write-offs of
slowing or non-moving finished goods stocks.
What is “One piece flow”?
TPS is also sometimes called “One piece flow” production system. Lot and
batch sizes are continuously minimized and reduced as close as possible to one
piece. Conventional manufacturing systems which practice big batch
production to attain efficiency and justify long set-ups, will tend to
overproduce and push unneeded stocks to the next station. To make smaller
batches and lots economical, TPS practices set-up time reduction. As a result,
a TPS line can operate as a mixed-model line, meaning it can produce or
assembly different models at the same time or same run without practically no
lost time between set-ups. A mixed-model line can operate with a much smaller
lot size for each product model, and can therefore synchronized more easily
with the actual demand patterns than a batch based system. It can mass
customize rather than just mass produce. The work stations in a line operating
with one piece flow or minimum work-in-process between them are said to be
coupled or synchronized with a high degree of dependency. To operate, such a
line must have very reliable work stations and strong teamwork. In
conventional manufacturing lines, on the other hand, there are high levels of
WIP between and inside work stations. The stations are de-coupled,
unsynchronized, and virtually act independent of each other. Less teamwork
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and communication, poor feedback and slow corrective response action are
observed. One-piece flow lines are highly productive and in general produce
better quality because every station or worker takes good care of every piece it
produces before sending it the next station or worker one at a time. The
receiving station, receiving only one piece at a time, also become very sensitive
to quality and would not want to accept a defect.
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rtd@aim.edu
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What is SMED (Single Minute Exchange of Die)?
To produce high variety of products at low cost in one line or to produce with
smaller lots economically as dictated by lean principles, it is necessary to cut
set-up time and consequently set-up costs. This set-up time reduction program
is called SMED or Single-Minute-Exchange-Of-Die. The press die or mold
usually takes hours to change or replace and this long set-up encourages the
production or pressing of big batches and long production runs that go against
the principle of lean and one-piece-flow. In order to achieve economical small
lot production, the set-up time is ideally reduced to minutes or one minute from
hours. The set-up process is shortened using the principles of kaizen and
process simplification. SMED is now a generic lean concept that is applied not
only to press operations, but to any equipment or process that have long set-ups.
A typical tire change may take 30 minutes or more, but the Formula One pitstop maintenance crew can replace 4 tires in 6 seconds while doing other tasks
like refueling using principles very similar to SMED.
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What is Heijunka?
For a lean one-piece flow system to work, the production must be smooth.
Heijunka means production or workload leveling to create a stable process.
Without heijunka, a lean line will be erratic and costly to operate because of
peaks and valleys in demand pattern. The TPS applies heijunka to production
volume and product mix. To level volume, customer orders are usually pooled
together and production schedules are leveled. To level product mix, TPS uses
mixed-model lines with short set-ups to produce smaller lots of every model.
What is Kanban?
To ensure the “pull” production flow, TPS employs a control mechanism
across the manufacturing process called “kanban” which means signboard in
Japanese. The kanban system serves as an effective and visual production
control mechanism of the TPS at the shop floor level and ensures timely and
synchronized production and delivery of the right quantity across the entire
manufacturing chain and supply chain.
In practice, kanban serves as an internal purchase order or PO between work
stations. When a customer orders, he issues a PO to the supplier which then
processes that order. In a way, the PO triggers the production or withdrawal
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from warehouse, and delivery of the exact amount ordered. Without the PO,
the supplier cannot deliver anything; and with the PO, the supplier cannot
deliver more than the quantity specified in the PO. Needless to day, the
supplier cannot deliver later than the specified date in the PO or risk being
penalized. This basic supplier-customer relationship is implemented in the
manufacturing process between work stations using the kanban as the trigger
rather than a PO. In order to comply with the TPS rule no. 2 “The next process
gets only what it needs from the prior process”, each station will issue a kanban
to the prior station which then produces and delivers the exact item, with the
right amount, at the right time and place specified in the kanban. Without a
kanban from its internal customer(s), no station can produce nor deliver to
anyone - thus behaving like a typical supplier. A kanban, is similar to a PO in
that contains the names or part number needed, quantity required, date and time
required, and place or delivery. What it does not have is price, since work
stations do not pay each other. Also unlike the PO, the kanban does not allow
earlier delivery.
The kanban is typically made of cardboard or plastic and attached to the part or
its container or bin. A work station receives the kanban, typically attached to
empty bins from the next process, refills them with the required parts and
quantity, and sends the filled up bins back to the next process for its usage.
Once the bins are used and emptied, these are sent back to the prior process
with the kanbans for replenishment, and the cycle repeats itself. The delivered
parts may be delivered and unloaded at the factory temporary storage site or
more typically directly at the point of use, e.g. assembly point where the parts
are used immediately. In some cases, the containers or bins, serve as the
kanban itself.
Under TPS, the factory, instead of issuing and sending PO’s to its suppliers,
sends supplier kanbans which are similar to the internal kanbans. The supplier
must then comply strictly as to the exact part number, quantity, timing, and
delivery points indicated in the kanbans it receives. Suppliers under the kanban
system, must delivery more frequently then traditional suppliers, sometimes as
often as thrice daily instead of once a month. They are not allowed to deliver
early nor late. They have to deliver mixed parts and smaller lots if the kanbans
demand so. Just-in-time suppliers are carefully selected and trained thoroughly
by Toyota on lean principles and practices so that they can cope with the strict
system flawlessly. Toyota forms strong and reliable supply chain partnerships
with these key suppliers rather than just buy or purchase parts from them.
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E-kanbans or electronic kanban is an improvement over the physical kanban
which can be lost, damaged, error-prone because of the need for manual data
entry. Instead of written or printed kanbans, kanban data are sent
electronically by a station to the prior station to trigger production and delivery.
The control of e-kanbans can be integrated into the factory’s information
system or manufacturing resource planning (MRP) systems.
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rtd@aim.edu
www.rtdonline.com
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What is Waste?
The elimination of waste is the primary goal of any lean system. In effect, lean
declares war on waste – any waste. Waste or muda is anything that does not
have value or does not add value. Waste is something the customer will not
pay for. When the great Italian sculptor Michelangelo was asked what he was
sculpting, he responded he was not sculpting but releasing the figure (value)
inside by removing the unnecessary rocks (wastes). Like Michelangelo, we
should eliminate all forms of wastes in any process or product until only what
is valuable remains. The key is to spot waste and then stop waste.
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There are two types of wastes: obvious wastes and hidden wastes. It is
important to uncover and eliminate the latter since they are usually bigger.
Wastes take the shape of an iceberg, the tip consists of the obvious wastes
while the unseen bulk under the water contain the hidden wastes. Wastes are
not necessarily ugly, and most are outside the waste can! Waste can be in the
form of unnecessary output, input, or processing. It can be in the form of
materials, stocks, equipment, facilities, manhours, utilities, documents,
expenses, motion, and other activities that do not add value.
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The steps to effective waste elimination are:
1.
2.
3.
4.
5.
Make waste visible.
Be conscious of the waste.
Be accountable for the waste.
Measure the waste.
Eliminate or reduce the waste
In other words, before one can stop waste, he should able to see it, recognize it
as waste, identify who is responsible, and finally appreciate its size and
magnitude. Waste that is not seen cannot be eliminated. When something is
denied as waste, it also cannot be stopped. When one refuses to accept
responsibility for the waste, then he will not eliminate it. Finally, when the
waste is not measured, people may think it is small or trivial and therefore will
not be motivated to stop it. As the saying goes “What is not measured, is not
improved”.
Rene T. Domingo
rtd@aim.edu
www.rtdonline.com
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Muda, Mura, Muri
Aside from “muda” or wastes, the lean system also attacks and avoids “mura”
or overload or overburden and “muri” or unevenness. Mura refers more
specifically to overloading an equipment, facility, or human resource beyond
its capacity. This undue stress may cause downtime, defects, delays, and even
disasters. Muri refers to unevenness in production volume. The wild
fluctuations due to extreme highs (peaks) and lows (valleys) in production
scheduling cause periods of overload and long idle time. One way to reduce
muri is to implement heijunka or production leveling. In a way, mura and muri
also cause wastes but in a particular way. Muda, mura, and muri cause
inefficiencies and high costs in any operation.
What are the seven types of wastes or “muda”?
A lean system declares war on wastes or “muda”. These wastes are classified
into 7 types:
Over-production waste
Definition
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 producing more than what is needed
 producing faster than what is needed
Causes
 volume incentives (sales, pay, purchasing)
 high capacity equipment
 line imbalance; poor scheduling/shifting
 poor production planning
 cost accounting practices that encourage build up of inventory
Over-production waste occurs when more goods are produced than can be sold,
resulting in idle finished goods inventory. Over-produced goods are often
hidden wastes since many think they are assets with value, when in fact most of
them may be obsolete or costing the company unnecessary expenses just to
keep them until they can be sold if ever. The just-in-time, pull system, and
kanban rules prevent over-production wastes. Also, lean systems favor smaller
equipment over large ones to avoid overproduction due to high but unnecessary
capacity utilization.
Processing waste
Definition
 non-value added man processing
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 non-value added machine processing
Causes
 unclear customer specifications
 frequent engineering changes
 excessive quality (refinements)
 inadequate value analysis/value engineering
 unclear work instructions
Processing waste comes from unnecessary processing that does not add value
to the item being produced or worked on. Examples are additional steps that
do not enhance quality or steps that simply adds excess quality which
customers do not require. Unnecessary documentation is also a form of
processing waste. Identify value-adding and non-value adding activities in the
process using techniques such as value stream analysis and the waterfall
diagram.
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Transport waste
Definition
 unnecessary material movement
 unnecessary tools or equipment movement
Causes
 poor route planning
 distant suppliers
 complex material flows
 poor layout
 disorganized workplace
 line imbalance
When anything – people, equipment, supplies, tools, documents, or materials –
is moved or transported unnecessarily from one location to another, transport
waste is generated. Examples are transporting the wrong parts, sending
materials to the wrong location or at the wrong time, transporting defects, and
sending documents that should not be sent at all. One way to cut transport
waste is co-location, wherein customers are served by nearby suppliers, usually
less than one-hour driving distance away. Departments working with each
other or serving each other are also put near each other to cut transport waste.
For example, materials and tools departments may be moved, relocated, or prepositioned beside or nearer the user departments or their internal customers.
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Waiting time waste
Definition
 man idle or waiting time
 machine idle or waiting time
Causes
 unsynchronized processes; line imbalance
 inflexible work force
 over-staffing
 unscheduled machine downtime
 long set-up
 material shortage or delay
 manpower shortage or delay
When resources like people and equipment are forced to wait unnecessarily
because of delays in the arrival or availability of other resources including
information, there is waiting time waste. Waiting for late attendees in a
meeting, waiting for tools to start work, waiting for a signature for a process to
continue, waiting for a late vehicle to transport workers to a project site are
examples of this waste.
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Inventory Waste
Definition
 excessive process (WIP) inventories
 excessive raw material inventories and supplies
Causes
 over-production
 imbalanced line
 big batch sizes
 long lead times
 local optimization (turf mentality)
 large minimum order quantities
 high rework rate
 JIT-incapable suppliers
 lack of material requisition and issuance standards
Inventory wastes come from the purchasing, issuance, storage of excess or
excessive supplies, materials, and other resources. This waste can also be
caused by overproduction as excess materials and work-in-process are
accumulated. Inventory waste is often due to lack of planning and failure to
match purchases with the actual consumption or usage rate of a particular
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resource. Another example is the storing of slow-moving and obsolete stocks
like tools and materials.
Motion Waste
Definition
 unnecessary movement and motions of worker
Causes
 poor lay-out
 disorganized work place and storage locations
 unclear, non-standardized work instructions
 unclear process and materials flow
Motion waste happens when unnecessary body movements are made when
performing a task. Examples are searching, reaching, walking, bending, lifting,
and other unnecessary bodily movements. Workers commit this form of waste
by searching for tools or documents when their workplace is cluttered or
disorganized.
Defects
Definition
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 processing due to the production of defects
 processing due to rework or repair of defects
 materials used due to defect and rework
Causes
 unclear customer specifications
 incapable processes
 lack of process control
 unskilled personnel
 departmental rather than total quality
 incapable suppliers
Quality is doing the right thing right the first time. It is about prevention and
planning, not correction and inspection. Bad quality or defects do not only
result in customer dissatisfaction and damage to company image, but also in
wastes due to additional costs and time to recall, rework, repair, and replace the
defective items. Continuous quality improvement and preventive measures are
the most effective means to cut defect wastes.
How does one distinguish obvious from hidden wastes?
It is important in lean thinking that one can distinguish hidden from obvious
wastes, otherwise only the trivial obvious wastes will be reduced. Imagine a
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factory producing 10,000 pieces of bottle caps a day. If one cap accidentally
falls on the shop floor from the production line, the worker may not pay
attention to it nor pick it up, being too busy in meeting his daily goal. If we
replace the cap with a 25 cent coin, he would most like pick it up however.
The difference is he does not see the value (or conversely the waste) of the cap
on the floor while he sees the coin’s value or its waste if he does not pick it up
and pocket it. Most hidden wastes are not actually “hiding” or unseen. They
are visible but not recognized as waste because we do not normally attach
value or cost to these. We may see waste in defects or scrapped items, but not
in good products called inventory neatly arranged in shelves which in reality
may be more wasteful in terms of carrying costs. Somebody walking or
loitering aimlessly in the office or factory may be considered wasting time, but
once he carries something, like an empty envelope, his loitering will be
unnoticed. In the same vein, a loaded vehicle moving may be more wasteful
than an empty one, if the former is carrying the wrong item or going to the
wrong place. Somebody pushing a wheelchair with a patient on it may be more
wasteful than one pushing an empty wheelchair if the patient can walk! A
clerk who sits in front of his desk doing nothing the whole day may be less
wasteful than one writing a report the whole day if nobody reads the report in
the first place. The first clerk is just wasting time, the second is wasting time
and paper. Consider a worker standing in the middle of the factory the whole
day – an obvious waste easily recognizable and stoppable. But suppose he
stands in front an equipment (press, printer, or fax machine) the whole day just
watching it operate, surely most would think he is working when in fact he is
just as wasteful as the first worker.
Often waste can be made visible if the measurements are clear and easily
understood. A taxi meter is a good example. When riding a taxi, we always
can see how much the trips costs at anytime. On the other hand, the household
electric utility meter is hard to understand and will not help us cut wasteful
electric consumption until it is too late, i.e., when the monthly bill arrives.
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What is takt time?
Suppose a line has to produce 960 units a day to meet market demand. If it
operates 8 hours daily, then it must produce one unit every 30 seconds. This
target cycle time is called takt time which serves like a metronome that the
process must achieve in order to meet the demand without overproduction.
Takt time is the basis of the lean principles of one-piece-flow, just-in-time, and
pull production. It assures the continuous and perfect match of capacity with
demand and avoids overproduction and inventory wastes. A process cycle
greater or less than the takt time results in two kinds of wastes –
overproduction or waiting time for the next process or customer. In process,
we should identify, remove, or improve the bottleneck operations, the slowest
in the process, that may cause this mismatch or imbalance. A lean line is a
balanced line running and producing with the takt time as its rhythm.
What is visual control?
When a problem like defects, downtime, or wastes occurs, it must be known
and corrected immediately. In order to improve and reduce response time to
problems, lean systems adopt visual control – the principle of using
conspicuous and recognizable signals and signs in the shop floor that will
immediately alert those concerned about the location, source, and nature of the
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problem. Visual signals can take the form of sounds, lights, dials, labels and
other indicators which can be electronic or non-electronic. The other use of
visual controls is to clearly indicate the status of any process or equipment,
whether it is normally or abnormally operating or being used. When a line
encounters a problem, a worker pulls an andon cord which triggers a sound
alarm or stops the line to alert his supervisor or seek help. An electronic andon
board may also light up in the factory, indicating the location or number of the
problem line. The kanban card, another visual control example, indicates the
number of pieces to be produced or delivered to the next station. If the kanban
is a bin, the bin serves as the visual control for overproduction once it is
overfilled. Colors lights attached to equipment called andon lights, similar to
traffic lights, indicate its operating status – green for normal operations, red for
breakdown, yellow for set-up, and white for waiting for parts. Tool boards
which painted outline of tools, like hammers or pliers, immediately show
which tools are missing and where to place or hung returned tools. Document
markers similarly indicate which documents were borrowed and where to
return them.
What is jidoka?
The jidoka principle means that a lean process, even running at high speed, will
automatically stop or be stopped by an empowered operator when a problem
like defects or wastes is detected, thus preventing the problem from going
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downstream. Operators need not guard or watch over jidoka-enabled
equipment. Jidoka is like smart automation or “autonomation” compared to
dumb automation which characterizes many equipment and processes. For
instance, many copiers and printers will continue to produce unclear output for
lack of ink until the operator turns them off. In the factory, many automated
usually high speed machines without jidoka can produce mountains of defects
when left unattended. By incorporating smart sensors in equipment and
processes, we can prevent and reduce wastes through jidoka. The jidoka
principle is exemplified by the andon cord that a line operator can pull to shut
down a line when he experiences a problem, like delays or defects. Jidoka is an
application of the lean principle of built-in quality or quality at the source.
What is poka-yoke?
Another built-in quality principle, similar to jidoka, is poka-yoke or mistakeproofing the process. While jidoka will stop the production of more defects or
wastes, poka-yoke, a step higher, will prevent their production. In other words,
poka-yoke can enable a process to achieve zero defect. Pokayoke are
inexpensive devices or modifications of process and equipment that stop it
when it senses that a defect is to be made or wrong task is about to be executed.
The work stoppage may trigger also an andon alarm to alert the operator.
Examples are sensors that check if the right part or raw materials are fed to the
equipment before it is worked on. The pokayoke will automatically stop the
equipment and operator from working on the wrong or incomplete part. It will
also prevent processing a part wrongly loaded or set-up. A pokayoke may also
check if the prior process has been done on a part before the next process is
initiated, thus preventing the further processing of a defect. A sensor pokayoke
can also stop work if a tool such as a drill bit is broken or worn out. A
pokayoke can turn off a machine that does not have the correct air pressure or
is operating outside standards parameters.
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What is root-cause analysis?
Before a problem, like waste or defect, can be solved and eliminated, its root or
real cause must be discovered and stopped. Root cause analysis is a systematic
analysis of the problem and goes beyond finding the obvious and superficial
causes or symptoms and then treating them. It results in a long term if not
permanent solution of the problem.
One powerful technique of root cause analysis is the 5 Why’s questioning
method. When a problem is defined, a 1st Why is asked to determine the
immediate cause. Then a 2nd Why is asked to determine the cause of this
immediate cause. After a series of Why’s usually not exceeding 5, the root
cause is usually arrived at and a countermeasure can be developed. For
example a worker produces a defect. Why? He was using a defective tool.
Why? The tool room did not check the tools it issued. Why? It does not have a
proper tool maintenance program. Solution: Develop and implement and
effective tool maintenance to program to reduce tool-related defects.
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Another common root cause analysis technique is the fishbone analysis also
called Ishikawa chart, named after its Japanese developer. The problem
becomes the head of the fish. A spine is drawn from it and major bones are
then drawn from this spine. Each bone represent possible causes of the
problem arrived at usually by group brainstorming. The major bones are
usually the 4 M’s – man, machine, method, and materials. Minor bones are
drawn from each of these major bones, indicating specific causes under each
category. From the possible causes, the project team selects and determines the
probable causes, and from these the actual cause or causes of the problem. It
then develops the solution from this analysis.
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What is Kaizen?
Kaizen means non-stop or continuous process improvement that anyone in the
company can do. Kaizen is a Japanese term consisting of two characters- "kai"
meaning "change" and "zen" meaning "good", thus together meaning
"improvement." Since kaizen in continuous, it does not stop or need a reason to
sustain it. The motto of kaizen is “There is always a better way of doing
anything.” Improvement process starts by correcting the wrong way to make it
right or meet standards. Then the right way is improved continuously through
kaizen, i.e., higher and higher standards are set and achieved. There is no best
way – consequently the process does not stop. Continuous improvement must
done whether the process is delayed or on time, whether the company is
profitable or not, or whether the customers are complaining or not. Kaizen can
enable a company to achieve higher and higher standards of productivity,
quality, and service. Kaizen follows the Plan-Do-Check-Act (PDCA) cycle of
improvement. Plan means select the process to improve. The Do or implement
the improvement plan. Check means verify the results. If the results are
favorable, then Act or make the new process the new standard. Then Plan
again the next PDCA cycle of improvement to raise the process standard anew.
Lean processes must be constantly improved with kaizen to reduce waste and
inefficiencies. Kaizen does not require big expensive improvements. It favors
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incremental, inexpensive, and common sense solutions to process problems
like defects and delays. It can be learned and implemented by rank-and-file
employees, office staff, as well as managers – in fact any one who does a
process or procedure repeatedly at work. Kaizen can be a company-wide
program that welcomes both individual as well as small group ideas and
suggestions.
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One important kaizen principle, expounded by Taiichi Ono of Toyota, one of
the pioneers of TPS, is “Use your head, not your money”. Kaizen is not about
throwing money and resources at problems. By working smarter, one can do
effective kaizen improvements without investments. To simplify a process
using kaizen, one can eliminate unnecessary steps, combine related steps (do
them in parallel), or change sequence of steps. Using these three simple
principles, kaizen can speed up a process, cut its costs without added resources
like equipment and manpower.
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Kaizen also applies the process thinking approach. In this approach, one looks
at the output and the input, and finds the efficient processes to transform input
to output, e.g., converting a customer order to order fulfillment or delivery. On
the contrary, the traditional approach is the “silo” system in which the focus is
the efficiency of the departments or “silos”.
What is 5S?
5S is the company housekeeping program that is implemented in all areas –
factory, offices, warehouse, comfort rooms, stairs, canteens, hallways, parking
area, etc. Like kaizen, it enjoins all employees to keep their workplace always
clean, clutter-free, and well organized. 5S is the acronym of the Japanese terms
1.
2.
3.
4.
5.
seiri (sorting)
seiton (organizing)
seiso (cleaning)
seiketsu (standardizing)
shitsuke (training and discipline)
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Seiri means to classify items into necessary and unnecessary, and remove the
unnecessary called clutter from the workplace, particularly from hidden areas.
Removal can mean relocate to a more distant location where it will not obstruct
work or outright disposal. Seiton means organizing the necessary items for
easy and efficient access and retrieval. This includes proper labeling and
storage. Seiso or “sweep” means cleaning the workplace of dust or dirt,
including repainting. Seiketsu means setting standards for procedures to
implement the first 3 S’s. Examples are standards on when and how to clean,
who will clean, how to store and label items, how to distinguish and collect
clutter, who is in charge of particular 5S zones which may consist of several
workplaces, and how to do 5S audits. Finally shitsuke means implementing and
sustaining the program through proper training and instilling discipline in all
employees.
The goals of 5S are improve quality, safety, and efficiency in the workplace
through proper organization, cleaning, standards, and discipline. 5S creates a
visual workplace, visitor-ready all the time like a showroom which one can be
proud of. Most 5S activities are done by the workers and employees
themselves rather than a dedicated housekeeping staff. A 5S rule is the “30
second rule”, meaning that if a workplace is properly organized and maintained
through 5S, one should be able to get any tool, item, or document required or
requested within 30 seconds. Thus 5S can reduce wastes due to unnecessary
walking, searching and waiting.
What is control of variation?
Wastes occur when customers’ specifications or process targets are not met, or
completely met. It is important therefore to control variation in the process so
that its outputs may lie within or close to these targets. Variation control
means ensuring process stability through process design and process control.
In process design, it is important to have the appropriate process capability that
will match the variation or tolerance given by the customer – external or
internal. Process control means ensuring that a capable process is always
operating within the given upper and lower control limits, using process
monitoring techniques such as Statistical Process Control (SPC) and Control
Charts. Variation control means good centering and good clustering. Imagine
a dart target. The goal is to have all three darts land inside the bulls eye – this
is perfect control of variation. A process out of control can mean 1) all three
darts are way outside the bulls eye, but clustered together 2) the darts, though
far apart from each other or dispersed, surround the bulls eye but lie near yet
outside of it and 3) the darts are dispersed and away from the bulls eye. In case
1, we have good clustering, but poor centering. In case 2) there is poor
clustering, but good centering. In case 3), both clustering and centering are
poor. In this last scenario, if this were a process, wastes, in the form of defects,
rejected and reworked items, will be maximum. The measurement of the
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centering of an output is its average or mean, while that of its variation or
dispersion is the standard deviation or variance.
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What is Six-sigma?
Six-sigma is a quality improvement method pioneered by Motorola and GE.
Projects are implemented following the DMAIC principle (Define, Measure,
Analyze, Improve, Control). Six-sigma aims to achieve about 3 defects per
million (dpm) by reducing variation and improving process capability. A sixsigma process has a process capability of 2, meaning its output has quality
twice that required by the customer. Six-sigma practitioners are classified into
Green, Black, and Master Black belters, depending on the skills and project
implementation success they have achieved. Lean Six-Sigma is a methodology
of cutting wastes using the six-sigma quality improvement principles.
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What is Total Productive Maintenance (TPM)?
Total Productive Maintenance is an integrated maintenance system of
improving employee productivity and safety, and equipment and process
efficiencies. Lean companies usually have TPM instead of just the traditional
preventive or corrective maintenance programs that focus mainly on equipment
condition. TPM has three major components: preventive maintenance,
autonomous maintenance, and overall equipment efficiency (OEE). Preventive
maintenance is the planned maintenance of equipment to prevent unscheduled
breakdowns which cause downtime losses. Autonomous maintenance
empowers machine operators and other process owners to do routine
maintenance to minimize downtime. This requires training and high sense of
commitment. OEE is a composite measurement in % of equipment or process
efficiency that considers availability, performance rate, and quality of the
process. The OEE formula is availability x performance x quality. OEE aims
to cut 6 major losses classified into three types of waste: availability loss due
to breakdown and long set-ups, performance loss due to idling and slow speeds,
and quality loss due to defects and poor yields. OEE also aims to improve the
ratio of useful operating time to planned operating time.
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What is gemba?
Gemba in Japanese means “actual place”. In practice, it means shop floor
management sometimes known as “management by walking around” to get
facts instead of staying in the office reading reports. Another term for gemba is
“management by facts”, meaning doing thorough analysis and making sound
decisions based on actual facts coming from actual operations. Related to
gemba is the concept of “genchi-genbutsu” which means going to the actual
scene (genchi) to see or verify the actual thing (genbutsu). Both gemba and
genchi-genbutsu are powerful and necessary concepts in promoting kaizen and
finding hidden wastes or “muda”. Attention to details is very important in
process analysis in kaizen.
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What is hoshin kanri?
Hoshin kanri which means “policy deployment” is the planning system of lean
companies. It consists of goal setting based on mission/vision, strategy
formulation – both long and short term, performance measures, deployment
and communication of strategies and goals down to the lowest level of the
organization, milestones for monitoring implementation and progress, and a
review process to gauge performance and achievements. The key in hoshin
kanri is everyone’s understanding of his or her role in helping achieve the
company’s goals and strategies, and his or her involvement and participation in
the planning process.
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What is target cost?
Traditionally, a product is priced and sold after determining its manufacturing
cost and the desired profit margin is added by management. This common
method is known as the cost-plus approach. The formula here is Price = Cost +
Profit. The sequence in decision making is Cost, Profit, and lastly Price. The
problem here is that the selling price may not be affordable to customers when
the base costs are high. Most lean companies like Toyota use a different
approach known as target costing. First the price the market wants or saleable
price is determined, usually by market research. The management sets its
profit goal which is them subtracted from the price to get the cost, or target cost,
which the company must achieve to be able to sell the product profitably. The
formula then becomes Cost = Price – Profit. Or more accurately, Target Cost =
Price – Profit. The sequence is decision making in this case is Price, Profit, and
lastly Cost. Target costing is definitely more effective than the traditional
approach since it is market-driven, rather than cost driven. It starts with price
or the customer in mind, rather than the internal cost of the company.
Moreover, target costing encourages kaizen and lean initiatives to cut costs and
wastes. If the actual cost is higher than the target cost, the company and all its
departments are bound to continuously reduce the difference in order to meet
the company’s sales and profit goals.
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What is benchmarking?
Benchmarking is finding, and then copying or adapting, the world’s best
practices in performing particular processes that a company wants to improve
usually through kaizen. The model may be a company, organization, institution
within the industry or outside the industry. The former is called competitive
benchmarking and the latter is non-competitive or functional benchmarking.
What is a lean culture?
The success and sustainability of a lean system depends on the strength of its
foundation which lean culture. The elements of lean culture are lean leadership,
lean mindsets, employee empowerment, and process ownership. A company
has a lean culture when everybody, from the lowest rank-and-file to top
management, are working together to cut all forms of wastes continuously as
shown by their practices, actions, behavior, and attitudes. In particular,
management provides leadership by formulating strategies, policies that
support and encourage lean initiatives, and by creating an open working
environment conducive to spotting, reporting, and stopping wastes. Everyone
under a lean culture has a strong sense of company pride and process
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ownership. All are engaged and empowered to do continuous process
improvement.
Strong teamwork in a lean culture is not just evident within departments and
divisions, but also across all units of the company.
All, whether in production, support, and administration departments, have the
same shared goals which are derived from the company’s strategies. For
example, a tool keeper should not think that his job is just to keep and issue
tools. He should think that his real responsibility to give the right tools at the
right time to the production people so that they make the right products at the
right time so that the marketing people can sell and deliver them on time to the
company’s customers. In other words, the tool keeper’s job is to support sales,
just like the marketing and production people.
Employees show lean attitudes and mindsets when they look beyond their jobs
and departments, and think of the rest of the company and its future. For
example, imagine 3 aircraft mechanics doing the same work with the same
tools on the same aircraft at the same pay. One may be bored, the second
indifferent, and the third happy with what they are doing. When asked what
they are doing, the bored mechanic may reply: “I’m tightening a bolt”. The
second may say “I’m installing the engine.” The third may reply: “I’m making
sure the company will always release an airworthy aircraft to the customer.”
While all three are tightening bolts, and installing engines, the happy mechanic
thinks beyond his actual job assignment, and sees the bigger picture, and his
more important role in his company’s success. He has more pride with his
work, more passion, and clearer sense of purpose. He can do the same work
everyday happily with the utmost care and excitement, without ever getting
bored or maybe even without feeling tired. His work, compared to those of the
other two mechanics, will most likely have much better quality due to the
amount of attention he gives. In fact, he will be most motivated to find a better
way of doing his work through kaizen or continuous improvement.
Lean success happens through people and processes. Process improvement is
not enough. In addition to achieving the “hard” process targets such as delays,
defects, backlogs, wastes, inventory, rework, and turnaround time, we also
have to achieve the “soft” people goals of empowerment, engagement,
ownership, commitment, responsibility, and teamwork. Only by achieving
these two hard and soft goals, of right process run by the right people (with the
right attitudes) can business results be realized – higher sales, market share,
profitability, and competitiveness.
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